Method and apparatus for dispersion strengthened bond coats for thermal barrier coatings

ABSTRACT

A directed vapor deposition (DVD) method and system for applying at least one bond coating on at least one substrate for thermal barrier coating systems. The method and system provides for alloy strengthening in high temperature metallic alloys that can be melt or solid state processed to materials that one applies by vapor deposition. The creep strengthened coating contains nanoscopic particles of oxides, nitrides, borides, carbides, and other materials which are formed by reactive codeposition. An approach for reactive codeposition is plasma assisted directed vapor deposition. Accordingly, the resultant structure may be utilized for, but not limited thereto, high temperature coatings, e.g. for protecting rocket or power turbines, or diesel engine components. The resultant structure is has a greatly extended lifetime attributed in part to the elimination of coating spallation by the “rumpling” mechanism.

RELATED APPLICATIONS

The present invention claims priority from U.S. Provisional ApplicationSer. No. 60/398,384 filed Jul. 25, 2002, entitled “dispersionStrengthened Bond Coats for Thermal Barrier Coatings and related Methodand System thereof” the entire disclosure of which is herebyincorporated by reference herein.

The present application is also related to International Application No.PCT/US02/28654, filed Sep. 10, 2002 entitled “Method and Apparatus forApplication of Metallic Alloy Coatings,” of which is assigned to thepresent assignee and is hereby incorporated by reference herein in itsentirety.

GOVERNMENT SUPPORT

This invention was made with government support under the Office ofNaval Research -N00014-00-1-0438. The government has certain rights inthe invention.

FIELD OF THE INVENTION

The present invention provides a method and an apparatus for efficientlyapplying a bond coat to a surface for thermal barrier coating systemsusing a directed vapor deposition (DVD) approach, and more particularlyproviding a dispersion strengthened bond coat that has an improved lifeexpectancy by mitigating ill effects attributed to bond coat yield andcreep. The dispersoids on the bondcoat surface can also be used toimprove the adhesion of thermally grown oxides that are subsequentlyformed on the bondcoat.

BACKGROUND OF THE INVENTION

Metallic alloy coatings are widely used to create functionality that isnot possessed by the underlying material. A good example is the case ofthermal barrier coating (TBC) systems which are used for the thermal andoxidation protection of the high temperature components used in advancedgas turbine and diesel engines to increase engine operating temperatures(and therefore improve engine efficiency) and to improve componentdurability and life. The TBC's currently in use are multi-layer systemsconsisting of a Zirconia based top layer that thermally protects aninternally cooled, high temperature superalloy component, and anunderlying bond coat applied to the super alloy to improve its adhesionto the top coat and reduce the rate of oxidation. The bond coat istypically an aluminum containing alloy such as MCrAlY (M=Ni and/or Co)or an aluminum based intermetallic such as a nickel aluminide containingvarying amounts of Pt, and/or rare earth such Hf. When this layer isexposed to oxygen at high temperature it forms a well bonded, thin (˜1μm) thermally grown (aluminum) oxide (TGO) layer which impedes furtheroxidation and hot corrosion of the underlying component. This TGO layeris formed on the surface of the aluminum-rich alloy bond coat layer by achemical (oxidation) reaction. This reaction is not volume conserving.The oxide occupies a larger volume than the metal consumed. Significantstresses (up to ˜1G Pa) are therefore created when the oxide isconstrained by the underlying metal. Additional stresses are created bythermal expansion mismatch between the TGO layer and the other materialsin the system. If the bondcoat is insufficiently strong at thetemperature of use to resist these stresses, the TGO layer rumples andeventually causes failure of the system (by spallation of the top coat).The strength of the bondcoat is governed by its composition andstructure. Both are constrained by the methods used for its application.

Bond coats have conventionally been applied using a variety oftechniques depending on the materials system used. For example MCrAlYbond coats are applied using low pressure plasma spray (LPPS), electronbeam physical vapor deposition EB-PVD) and occasionally by sputtering.The aluminide bond coats are typically applied using a diffusion basedprocess. Such processes include pack cementation, vapor phasealuminiding (VPA), or chemical vapor deposition (CVD). The diffusionprocesses result in a bond coat with two distinct zones; an outer zonewhich contains an oxidation resistant phase (such as beta-NiAl) and adiffusion zone which consists entirely of the oxidation resistant phaseand secondary phases (such as gamma prime, gamma, carbides and sigma).

The primary function of the bond coat is to form a thin, slow growing,alpha alumina oxide layer (TGO) which protects the underlying componentfor oxidation and corrosion. This function is dependent on thecomposition and morphology of the coating. The composition is criticalto the formation of the TGO layer for two reasons. The first is the needto have an aluminum level high enough to support the continued growth ofthe protective aluminum oxide layer during the lifetime of the coatingsystem. As a TGO grows in service the aluminum content is continuallydecreased. When the aluminum content falls below a critical level,nonprotective oxides begin to form which lead to spallation of the TGOlayer. Thus, a large aluminum reservoir is desired. TGO formation canalso be effected by minor alloy additions which may occur as a result ofinter-diffusion between and bond coat and the superalloy substrate. Suchelements can increase the growth rate of the TGO layer and may promotethe formation of unwanted, nonprotective oxide scales. It also providesa means for sulfur and other oxide interface embrittling elements toleach the TGO layer. Ideally, inter-diffusion between the bond coat andthe superalloy should be limited both during the formation of the bondcoat and during service of the component.

The surface morphology of a bond coat can also effect TGO growth. Forexample, a dense coating free of open porosity is required to form aprotective scale on the coating surface. Open porosity results ininternal oxidation of the bond coat and oxidation of the underlyingcomponent. Another key morphological feature of the bond coat is itsgrain size. The presence of insoluble particles has been used to createfine grain sizes (x) which are thought to increase the lifetime of TBCsystems. Higher yield and creep strength bond coats are desired as theylimit the thermomechanical phenomena which lead to failure of the TBCsystem. However, these can be difficult to achieve with current processtechnologies.

Bond coat strength can in part be retained by insulating the metalliccomponent. The component and bond coat's temperature is then reduced,allowing it to last longer or to survive with less cooling air (coolingair reduces the performance of the engine). Recent work (See J. W.Hutchinson, M. Y. He, A. G. Evans, J. Mech. Phys. Solids, 48, 2000, pg709, herein incorporated by reference) has identified bond coat rumplingas a contributor to spallation of the ceramic top coat. This occurs bycreep of the bond coat resulting from stresses created during thermalcycling of the TGO/bond coat system. The typical bond coats are eitheraluminide (or platinum modified aluminide) or MCrAlY type coatings.These both contain a beta NiAl intermetallic phase, which is very weakat elevated temperatures. In addition to the work of J. W. Hutchinsonet. al., earlier work (See Duderstadt U.S. Pat. No. 5,498,484 andGoldman et al. U.S. Pat. No. 5,712,050, of which are hereby incorporatedby reference herein in their entirety) has suggested that strengtheningthe bond coats produces improved lives. This work was all performed withlow pressure plasma spray (LPPS) processing. Strengthening by addingsolid solution strengthening elements has been explored extensively.This approach is amenable to implementation by some of the processtechnologies in current use.

Work by Artz (See E. Arzt and P. Grable, Acta Mater., 46 (8), 1998, pp.2717-2727, of which is hereby incorporated by reference herein in itsentirety) has shown that Al₂O₃ dispersoids with sizes of 1-100 nmgreatly increase NiAl's resistance to creep, FIG. 2. Wittenberger et al.(See Structural Intermetallics, Ed. J. D. Wittenberger, TMS, 1993, pp.819-828, of which is hereby incorporated by reference herein in itsentirety) have shown similar improvements using AlN dispersoids, FIG. 3.These dispersoids can be resistant to coarsening at the use temperatureand therefore remain in a finely dispersed state. So called oxidedispersion strengthened (ODS) alloys are in widespread use.

The conventional processes currently in use for applying bond coatssuffer severe limitations when used for depositing finely dispersedparticles in a metal alloy bond coat. PVD processing has been used inthe past to produce dispersoids for strengthening (by Movchan) in copperand other structural materials. Movchan's work primarily was performedwith co-evaporation of an oxide to form the dispersoid. While reactiveevaporation is widely used for some applications (ard coatings, opticaland electronic primarily), its use to form stable dispersoids ofcontrolled size, volume fraction, and interparticle spacing in bondcoats for turbine airfoils has not been reported.

There is therefore a need in the art for a low cost deposition approachfor applying bond coats which contain stable, 1-100 nm diameterdispersoids with volume fractions up to 10% in bond coats for turbineair foils or any component on which a coating system may be to protectthe component from its environment. Such dispersoids mitigate the damageimparted on the components caused by yield and creep of the bond coat.Those at the surface of the bond coat can nucleate a preferred(corundum) aluminum oxide phase in the TGO layer. Further, there is aneed in the art for a deposition approach for applying bond coats thatenable the creation of a desirable dispersion and coating grain size inthe deposited bond coat.

In all such cases, the ability to deposit compositionally controlledcoatings efficiently, uniformly, at a high rate, with high partthroughput, and in a cost-effective manner is desired. Some illustrativeexamples of deposition systems are provided in the followingapplications and patents and are co-assigned to the present assignee 1)U.S. Pat. No. 5,534,314, filed Aug. 31, 1994, entitled “Directed VaporDeposition of Electron Beam Evaporant,” 2) U.S. Pat. No. 5,736,073,filed Jul. 8, 1996, entitled “Production of Nanometer Particles byDirected Vapor Deposition of Electron Beam Evaporant,” 3) U.S. Pat. No.6,478,931, filed Aug. 7, 2000, entitled “Apparatus and Method forIntra-layer Modulation of the Material Deposition and Assist Beam andthe Multilayer Structure Produced There from,” and correspondingDivisional U.S. application Ser. No. 10/246,018, filed Sep. 18, 2002, 4)International Application No. PCT/US01/16693, filed May 23, 2001entitled “A process and Apparatus for Plasma Activated Deposition in aVacuum,” and corresponding U.S. application Ser. No. 10/297,347, filedNov. 11, 2002, and 5) International Application No. PCT/US02/13639,filed Apr. 30, 2002 entitled “Method and Apparatus for EfficientApplication of Substrate Coating;” of which all of these patents andapplications are hereby incorporated by reference herein in theirentirety. The present invention discloses, among other things anapparatus and a method for applying a bond coating(s) on a substrate(s)in an improved and more efficient manner.

Other U.S. Patents that are hereby incorporated by reference herein intheir entirety include the following:

U.S. Pat. No. 6,096,381, Zheng (2000)

U.S. Pat. No. 6,123,997, Schaeffer et al. (2000)

U.S. Pat. No. 6,153,313, Rigney et al. (2000)

U.S. Pat. No. 6,168,874, Gupta et al. (2001)

U.S. Pat. No. 6,255,001, Darolia (2001)

U.S. Pat. No. 6,258,467, Subramanian (2001)

U.S. Pat. No. 6,273,678, Darolia (2001)

U.S. Pat. No. 6,291,084, Darolia et al. (2001)

U.S. Pat. No. 6,306,524, Spitsberg et al. (2001)

U.S. Pat. No. 6,436,473 Darolia et al. (2002)

U.S. Pat. No. 6,455,167 Rigney et al. (2002)

U.S. Pat. No. 6,461,746 Darolia et al. (2002)

U.S. Pat. No. 6,485,845 Wustman et al. (2002)

U.S. Pat. No. 6,585,878 Stangman et al. (2003)

U.S. 2002/0110698 A1 Sing (2002)

SUMMARY OF THE INVENTION

The present invention provides a method and an apparatus for efficientlyapplying a dispersion strengthened bond coating to a surface for thermalbarrier coating systems using a directed vapor deposition (DVD)approach. To overcome the limitations incurred by conventional methods,the present invention uses a modified energetic beam directed vapordeposition (DVD) technique to evaporate and deposit compositionally andmorphologically controlled bond coats at high rate. In one modality, thepresent invention DVD technique uses the combination of an energeticbeam source (e.g., beam gun) (capable of processing material in a lowvacuum environment) and a combined inert gas/reactive gas carrier jet ofcontrolled composition to create engineering films. In this system, thevaporized material can be entrained in the carrier gas jet and depositedonto the substrate at a high rate and with a high materials utilizationefficiency. The velocity and flux of the gas atoms entering the chamber,the nozzle parameters, and the operating chamber pressure can all besignificantly varied, facilitating wide processing condition variationand allowing for improved control over the properties of the depositedlayer. In particular, under some (higher pressure/evaporation rate)processing conditions, nanoscopic particles can be reactively formed inthe vapor and incorporated in the cooling.

In another aspect of the present invention, by employing plasmaenhancement, multisource crucibles and appropriate process conditioncontrol, the morphology, composition, dispersoid size and concentration,the bondcoat grain size and porosity of deposited layers are allcontrolled. In a second modality, the present invention uses a differentevaporation source to reactively create dispersoids which are thenentrained in the vapor plume used for depositing the coating. In a thirdmodality, dispersoids are created before deposition and are entrained inthe noble gas stream and used to transport the bond coat vapor to thecomponent surface. In modalities one, two, and three a plasma may alsobe used to control the bond coat structure. In all modalities, theresult is a low cost deposition approach for applying bond coats whichcan have compositions and dispersoids distributions which are difficultto deposit using other conventional approaches.

The DVD apparatus and method comprises a vacuum chamber, energetic beamsource (e.g., beam gun), evaporation crucible(s), and inert/reactive gasjet. In addition, a plasma can be created. A substrate bias systemcapable of applying a DC or alternating potential to at least one of thesubstrates can then be used for plasma assisted deposition. The electronbeam impinges on at least one of the vapor flux sources contained in thecrucible. The resulting vapor is entrained in at least one of thecarrier gas streams. Hollow cathode arc plasma activation source may ormay not be used to ionize at least one of the generated vapor flux andat least one of the carrier gas stream. The ionized or non-ionizedgenerated vapor flux and carrier gas stream are attracted to thesubstrate surface by allowing a self-bias of the ionized gas and vaporstream or the potential to pull the ionized stream to the substrate.

In an alternative embodiment an end-hall ion source is modified tofunction as the evaporation and plasma creating system. FIGS. 10(A)-(B)show a modified gridless ion source of the type described by Kaufman andRobinson (See Operation of Broad Beam Sources, by Harold R. Kaufman andRaymond S. Robinson, Commonwealth Scientific Corp., Alexandria, Va., pp55-62, 1984). In the approach of the present invention a low voltageexterior electron beam is used to create a plasma in the throat of theevaporant source. The anode is axisymmetric with a central hole in whichis fitted a water cooled crucible, which in turn contains one or amultiplicity of evaporation sources. FIG. 10(B) shows a cross section.

In other preferred embodiments, the DVD apparatus and method comprises avacuum chamber having a radio frequency field that is used to ionize theevaporant and/or the carrier gas stream and a self and/or static orradio frequency bias voltage applied to the substrate that is used toprovide plasma enhanced deposition of the coating.

In other preferred embodiments, the DVD apparatus and method comprises atechnique for creating a plasma consisting of partially or fully ionizedevaporant or carrier gas stream that is used in combination with a selfor applied DC or RF bias voltage applied to the substrate to provideplasma enhanced deposition of a coating.

In a second embodiment, the present invention provides a method forapplying at least one bond coating on at least one substrate for forminga thermal barrier system. The method-includes: presenting at least onesubstrate; forming a bond coat on at least a portion of at least onesubstrate by a directed vapor deposition (DVD) technique; reactivelyforming dispersoids in said bond coat; and depositing athermal-insulating layer on the bond coat. In some embodiments thesubstrate is presented to the substrate in a chamber, wherein thechamber has an operating pressure ranging from about 0.1 to about 32,350Pa. The method may further include: presenting at least two evaporantsources to the chamber(could be one source as well); presenting at leastone carrier gas stream to the chamber; impinging said at least twoevaporant sources with at least one electron energetic beam (or otherenergetic beam types) in the chamber to generate an evaporated vaporflux in a main direction respective for any of the two evaporant sourcesimpinged by the electron beam; and deflecting at least one of thegenerated evaporated vapor flux by at least one of the carrier gasstream, wherein the carrier gas stream is essentially parallel to themain direction and substantially surrounds the evaporated flux, whereinthe evaporated vapor flux at least partially coats at least onesubstrate to form said bond coat, or any other coating or thin film.

In a third embodiment, the present invention provides an apparatus forapplying at least one bond coating on at least one substrate for forminga thermal barrier system. The apparatus includes a chamber, wherein thechamber has an operating pressure ranging from about 0.1 to about 32,350Pa, wherein at least one of the substrates is presented in the chamber.The apparatus further comprises: at least two evaporant sources (couldbe one source as well) disposed in the chamber; at least one carrier gasstream provided in the chamber; and an electron energetic beam system(or other energetic beam system) providing at least one electron beam(or other energetic beam). The electron beam (or other energetic beam)impinges said at least two evaporant sources with at least one electronbeam (or other energetic beam type) in the chamber to generate anevaporated vapor flux and deflects at least one of generated evaporatedvapor flux by at least one of carrier gas stream, wherein the evaporatedvapor flux at least partially coats at least one of the substrates toform a bond coat and reactively forms dispersoids in said bond coat.

In a fourth embodiment, the present invention provides component havinga thermal barrier coating system on a substrate thereof, the thermalbarrier coating system includes a bond coat deposited on at least aportion of the substrate by a directed vapor deposition (DVD) technique,wherein said bond coat comprises dispersoids in said bond coat; and athermal-insulating layer overlying at least a portion of the bond coat.The component may be produced by the present invention methods discussedthroughout this document. The advantages of the present inventioninclude, but are not limited to: improved use of expensive gases,increased deposition efficiency, and improved uniformity in the coating,

The result is a dramatically improved method for the efficientapplication of a bond coating to a surface for thermal barrier systemswherein the bond coat(s) has an improved life expectancy and performancedue to the mitigation of yield and creep effects.

These and other objects, along with advantages and features of theinvention enclosed herein, will be made more apparent from thedescription, drawings, and claims that follow.

DESCRIPTION OF THE FIGURES

The foregoing and other objects, features, and advantages of the presentinvention, as well as the invention itself, will be more fullyunderstood from the following description of preferred embodiments, whenread together with the accompanying drawings, in which:

FIG. 1 is a schematic illustration of a partial view of the substrateshowing a thermal barrier coating system on the substrate in accordancewith an embodiment of this invention.

FIG. 2 is a graphical depiction of the effect of aluminum oxidedispersoids that produce the beneficial effects. At 1500K, the stressrequired to cause a 10⁻⁴ s⁻¹ strain rate that must be increased from 15to 60 MPa in a fully recrystallized NiAl alloy containing aluminum oxidedispersoids.

FIG. 3 is a graphical depiction the effects of aluminum nitrides thatproduce the desired effect. The stress that is required to cause a creepstrain rate of 10-5s-1 must be increased from 29 MPa when no AlNdispersoids are present to 90-Mpa when 5 Vol % AlN is present in a NiAlintermetallic.

FIG. 4 is a schematic illustration of the directed vapor deposition(DVD) processing system. Included in the process are the ability toevaporate from two or more individual source materials and, optionally,the ability to ionize the evaporated flux using hollow cathode plasmaactivation. Optionally, may be evaporated by one source.

FIG. 5 is a schematic illustration showing the use of a two cruciblearrangement for alloy deposition using conventional electron beamevaporation.

FIG. 6 is a schematic illustration of the present invention showing theuse of multiple source evaporation in directed vapor deposition. Forexample, using a 100 kHz scan rate, a single e-beam can be scannedacross multiple, closely-spaced vapor sources for precise alloy ormultilayer deposition. The water-cooled copper crucible and independentsource feed motors make possible independent material feed andevaporation. The setup is shown schematically for Ni/Y/Al/Ptevaporation.

FIG. 7 is a schematic illustration of the hollow cathode plasmaactivation unit, optionally, used in the present invention DVDapparatus. The cathode plasma activation device emits low energyelectrons that ionize the vapor atoms and carrier gas. By properlybiasing the substrate the impact energy of both species can becontrolled.

FIG. 8 provides an enlarged partial view of the embodiment shown in FIG.7.

FIG. 9 shows a schematic representation of an alternative embodiment ofthe present invention, demonstrating the deflection of the main gas andvapor stream and a compensation of it by of an opposed gas injectionfrom the anode.

FIGS. 10(A)-(B) show a schematic representation of a modified gridlession source processing system, providing a partial elevation view andpartial cross-sectional view, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is an improved thermal barrier coating (andrelated method and system for making) which comprises, among otherthings, a) a substrate typically a nickel base superalloy, b) adispersion strengthened bond coat and c) a ceramic insulating layer orlayers on top. The dispersion strengthened bond coat in this inventionis novel in that, but not limited thereto, it produces improved coatingsystem life due to greater yield and creep strength. It may also improvethe adhesion of the TGO layer to the bondcoat and enable top coats ofpreferred morphology to be nucleated. The bond coat consists of one ormore metallic or intermetallic phases with a dispersoid of about 1-100nanometer diameter particles throughout. The volume fraction of thedispersoid is at least about 0.5% but can be varied from about <0.1 toabout >10%. The preferred compositions for the metallic or intermetallicportion are 1) Ni—50 atom % Al, 2) 50 atom% Ni+Pt—50 atom % Al.Additions of Cr, and oxygen active elements (such as Hf, Y, Zr, La, andother rare earth elements) can also be made. Addition of the oxygenactive elements to non-dispersion strengthened coatings has been used toincrease oxidation resistance, See FIG. 2. Here these elements may alsohelp to form particularly stable dispersoids (rather than aluminum oxideor nitride).

A process and system to produce these new bond coats is also invented.The process uses EB-PVD to form the coating either by reaction betweenthe evaporant and with a reactive gas present in the coating chamber(See FIG. 4), or by the addition of the dispersoids to the noble gasstream created in the system or externally. The reactive gas will reactwith the desired species (aluminum or one or more of the oxygen activeelements described above) in the gas phase to get the microstructurenecessary to produce an effective coating. By reacting in the gas phasea finer, dispersed oxide, carbide, boride, oxycarbide, nitride,Carbonitride, Nitrocarbide, or Carbooxide or other suitable dispersantcan be formed. Other suitable dispersoids would include, but not limitedthereto, as follows:

a) MX whereby M=Mn, Cr, Fe, Ni, Sc, Hf, Ti, V, Zr, Al, Nb, Ta, Si, or W,or combinations thereof and X=oxide, carbide, boride, oxycarbide,nitride, Carbonitride, Nitrocarbide, Carbooxide;

b) ZrO₂, Y₂O₃, Cr₂O₃, Al₂O₃-3 (13, 20, 40, or 50)TiO₂, TiO₂,Cr₂O₃—TiO₂—SiO₂, ZrO₂-8(13)Y₂O₃, ZrO₂-5(10)CaO, SiNC, SiC_(x)N_(y)(x+y=4), (Al,Fe)₂O₃, AlN, or AlY;

c) SiC, Si₃N₄, SiC_(x)O_(4-x), BC_(y)O_(3-y), SiNC, SiOC, TiN, Ti₂AlN,TiAl₃, TiB₂, AlB₂, or WC;

d) carbide, nitride, carbonitride, or boride of a 4b-, 5b-, or 6b grouptransition metal;

e) nitride, boride, or oxide of M; and/or

f) at least one kind of carbide, nitride, carbonitride, and boride ofFe, Co, or Ni.

The typical EB-PVD process used for bond coats is not capable of the gasphase reaction since it operates at very low pressure (typically apressure of less than 0.01 Pa). Furthermore, a method to energize theevaporative species and the reactive gas is necessary. Breaking thebonds of the reactive gas to make monotomic oxygen or nitrogen helps todrive the reaction in the gas phase as well. The DVD process has beenused to make initial coatings. The present invention DVD process mayoperate at pressures of about 1.0 to about 10 Pa (but may also operateat a range of about 0.1 to about 32,350 Pa). At these higher pressuresthe number of atomic collisions in the gas phase is much higher thantypical EB-PVD processing allowing for more reaction to occur. Also, useof a hollow cathode to inject electrons or other means of creating aplasma which will energize and ionize the vapor species will help tocause the reactions to proceed. Furthermore, biasing the substraterelative to the plasma created by the hollow cathode will drive theionized species to the substrate with a high energy. This has the addedbenefit of producing a denser coating that will have better properties.

Turning to FIG. 1, FIG. 1 schematically represents a TBC system 90 of atype that benefits from the teachings of this invention. As shown, thecoating system 90 includes a ceramic layer 96 bonded to the substrate 92with an overlay bond coat 94 having ceramic dispersoids 95 of an oxygencompound dispersed at least substantially throughout. To attain thedispersoids the ceramic is reactively created during the depositionprocess. The substrate 92 (e.g., blade, etc.) is preferably ahigh-temperature material, such as an iron, nickel or cobalt-basesuperalloy. To attain a strain-tolerant columnar grain structure, theceramic layer 96 is deposited by the desired deposition technique. Apreferred material for the ceramic layer 96 is an yttria-stabilizedzirconia (YSZ), with a suitable composition being about 4 to about 20weight percent yttria, though other ceramic materials could be used,such as yttria, nonstabilized zirconia, or zirconia stabilized by ceria(CeO₂), scandia (SC₂ O₃) or other oxides. The ceramic layer 96 isdeposited to a thickness that is sufficient to provide the requiredthermal protection for the underlying substrate 92, generally on theorder of about 125 to about 300 micrometers. The surface of the bondcoat 94 oxidizes to form an aluminum oxide surface layer (alumina scale)98 to which the ceramic layer 96 chemically bonds.

The present invention directed vapor deposition (DVD) apparatus andrelated method provide the technical basis for a small volume, low costcoating process capable of depositing the bond coat of a thermal barriercoating (TBC) system. DVD technology utilizes a trans-sonic gas streamto direct and transport a thermally evaporated vapor cloud to acomponent. The footprint of the vapor plume can be varied from adiameter of about 2-3 cm to as much about 20 cm or more. As a resultsmall airfoils, or portions of large airfoils (that are being repaired)can be coated with very little overspill and thus waste of the vaporcloud. Typical operating pressures are approximately in the about 6.67to about 66.7 Pa (but may also operate at a range of about 0.1 to about32,350 Pa) range requiring the use of inexpensive mechanical pumping. Inthis new process, material is thermally vaporized using a highvoltage/low power (about 60 or 70 kV/10 KW) axial e-beam gun (modifiedto function in a low vacuum environment). The vapor is then entrained ina carrier gas stream and deposited onto a substrate at high rate(about >10 μm min⁻¹ for a plume cross sectional area of about 50 cm²)and with a high materials utilization efficiency greater than ten timesthat of conventional EB-PVD processes. These characteristics combine tomake the present invention DVD process a low cost solution fordepositing bond coats onto gas turbine airfoils and other enginecomponents. Moreover, the bond coat deposition creates ceramicdispersoids that help prevent creep and other cracking of the substrateand coatings.

FIG. 4 shows a schematic illustration of the directed vapor depositionprocess. Using this process, dense nickel aluminide bond coats that aredesired for TBC applications have been produced. In DVD, the carrier gasstream 5 is created by a rarefied, inert gas supersonic expansionthrough a nozzle 30. The speed and flux of the atoms entering thechamber 4, the nozzle parameters, and the operating chamber pressure canall be varied leading to a wide range of accessible processingconditions. Critical to the process is the supersonic carrier gas streammaintained by achieving a high upstream pressure (i.e. the gas pressureprior to its entrance into the processing chamber), P_(u), and a lowerchamber pressure, P_(o). The ratio of the upstream to downstreampressure along with the size and shape of the nozzle opening 31 controlsthe speed of the gas entering the chamber 4. The carrier gas molecularweight (compared to that of the vapor) and the carrier gas speedcontrols its effectiveness in redirecting the vapor atoms via binarycollisions towards the substrate 20. As will be discussed later,alternative embodiments of the present invention process will provideother capabilities to evaporate from two or more individual source rodsand the ability to ionize the evaporated flux using hollow cathodeplasma activation.

Still referring to FIG. 4, the aforementioned DVD process isschematically shown in FIG. 4, improving the deposition efficiency,increasing the deposition rate, providing coating dispersoids, andenhancing the coating uniformity. As will be discussed later, the hollowcathode system 58 is optional based on desired operations. In apreferred embodiment, the carrier gas 5 is realigned so that it issubstantially in-line with the crucible 10. In this alignment, thecarrier gas flow is placed completely or substantially around thecrucible 10 so that the vapor flux 15 no longer has to be turned 90degrees towards the substrate 20, but rather can be simply focused ontothe substrate located directly above the evaporant source 25 formaterial A and R and evaporant source 26 for material C. Material A, Band/or C may include Y, Al, Ni, Pt, Co, Mo, Fe, Zr, Hf, Yb, and/or otherreactive elements that form the matrix of the bond coat and the ceramicdispersoids throughout the bond coat. The carrier gas 5 flowssubstantially parallel with the normal axis, identified as CL.Additionally, as will be discussed later herein, the nozzle 30 has anozzle gap or opening 32, through which the carrier gas 5 flows, isdesigned such that a more optimal carrier gas speed distribution forfocusing the vapor 15 is produced. Also shown is-the energetic beamsource 3, such as electron beam source, laser source, heat source, ionbombardment source, highly focused incoherent light source, microwave,radio frequency, EMT, or combination thereof, or any energetic beamsthat break chemical bonds and vacuum chamber 4.

Regarding component heating, TBC's are typically applied at a very hightemperature (e.g., 1050° C.). This temperature is achieved bypre-heating the blade before it is entered into the chamber. Due to theconfiguration of the system in the present invention, such that theblade is placed directly above the source and the carrier gas flow ratemay be decreased, the amount for radiant heat from the source is greatlyincreased and thus blade heating using a standard pre-heating furnacemay be realized.

Moreover, in the existing design of the conventional DVD system, boththe vapor and carrier gas flow pass through supersonic shock waves asthe gas and vapor move away from the gas flow nozzle. These shock wavesaffect the density and distribution of the vapor. When a coating surfaceis then placed such that it intersects the flow, the resulting atomicstructure of growing film can be affected by the distance from the gasflow nozzle to the coating surface (relative to the shocks in the flow).In the present invention system, there will still be supersonic shockwaves in the carrier gas flows emerging from the ring nozzle. However,since the vapor is no longer incorporated directly into that carrier gasflow, its distribution and density will be less affected by the shocksin the system. As a result, the present invention process will becomeless critically dependent upon the position of gas flow nozzle andcoating surface. Thus, when the geometry of the part being coateddictates a smaller (or larger) source to substrate separation, thepresent invention system design will be able to more easily accommodatesuch parts while still producing the desired atomic structure.

Another advantage of present invention nozzle design is that it may beused with larger source sizes without the need for adding significantlymore pumping capacity. The pumping capacity required for DVD is afunction of the nozzle opening area. Larger openings require morepumping capacity in order to reach the same chamber pressure thansmaller openings. Additionally, as the source size is increased, thenozzle opening size must be increased, and this is true for bothconfigurations. However, the area increase for the present inventionring configuration is much less than for the conventional circularshaped opening. For example, if one assumes that increasing the sourcesize from 0.0127 m to 0.0381 m requires a three fold increase in thenozzle diameter, the increased nozzle opening area can be calculated forboth configurations. It is found that the circular opening would have anine fold increase in area while the ring opening would have only a 2.76fold increase. Thus, a significant savings in the required pumpingcapacity and gas flow costs is achieved. The benefit of increasing thesource size is that the vapor emitting surface would be increased bynine fold, and in conjunction with the 3 to 4 time improvement in thedeposition efficiency, could lead to a deposition rate which is morethan 30 times higher than current DVD technology (i.e., greater than 500μm/min. is then possible based on current deposition rates (of 15 to 20μm/min.)).

Turning to FIG. 5, an exemplary illustration is shown wherein materialsare evaporated from two or more sources using either a single ormultiple electron beam gun arrangement. As shown in FIG. 5, in aconventional EB-PVD configuration, the film composition is stronglydependent on the position of the sources and the substrate position. Thecompositional uniformity and region of vapor mixing can be maximizedwhen the source spacing, s, is small and the source to substratedistance, h, is large. However, such a configuration is often notadvantageous as large source to substrate distances lower the materialsutilization efficiency (MUE, the ratio of evaporated atoms which depositonto the substrate) and the use of a small source size leads to reducedevaporation rates. This is not conducive to high rate deposition and issignificantly more costly than single source evaporation. Improvedmultisource deposition approaches are therefore desired which yieldcompositionally uniform vapor fluxes and a high process efficiency aretherefore desired.

As another aspect of the present invention, as illustrated in FIG. 6,there is provided an alternative embodiment, wherein vapor phase mixingcan be achieved by aligning two (or potentially more) sources 223, 224,225, 226 (evaporant materials A, B, & C) in line with a carrier gas flow205 and using electron beam scanning 203 to uniformly heat both (orplurality of) sources (optionally, may be achieved with one evaporantsource). The use of the carrier gas jet in this embodiment not onlyscatters the vapor flux toward the substrate, leading to a potentiallyhigh MUE (and high deposition rates), but also randomizes the vaportrajectory facilitating vapor phase mixing of the two (or plurality of)fluxes 216. A high MUE would allow for the use of small diameter metalsource materials, which could be spaced closely together to furtherimprove the compositional uniformity of the coating, while stillachieving a high rate of deposition. The composition of the depositedlayer could be systematically controlled by altering the electron beamscan pattern to change the surface temperature (and thus the evaporationrate) of each source material.

In one embodiment, the electron beam gun in the directed vapordeposition system has been equipped with a high speed e-beam scanningsystem (up to about 100 kHz) with a small beam spot size (<about 0.5 mm)to allow multiple crucibles to be placed in close proximity to oneanother for precise heating and vapor mixing. The carrier gas surroundsthe vapor sources and allows the vapor from the neighboring melt poolsto interdiffuse. The composition of the deposited layer can then becontrolled by altering the electron beam scan pattern to change thetemperature (and thus the evaporation rate) of each source material. Ineffect this is a splitting of the beam into two or more beams (if two ormore sources) with precisely controllable power densities. As a result,the present invention DVD system enables the evaporation of severalmaterials simultaneously and thus, precise composition control in thecoating can be achieved. Using a 100 kHz scan rate, a single e-beam canbe scanned across multiple, closely-spaced vapor sources for precisealloy or multilayer deposition. The water-cooled copper crucible andindependent source feed motors make possible independent material feedand evaporation. The setup is shown schematically for Ni/Y/Al/Ptevaporation. A single e-beam can be scanned across multiple,closely-spaced vapor sources for precise alloy or multilayer deposition.The water-cooled copper crucible and independent source feed motors makepossible independent material feed and evaporation

In an alternative embodiment, to endow the DVD process with the abilityto create dense, crystalline coatings, a plasma activation unit isincorporated into the DVD system. As will be discussed in greater detailbelow, plasma-activation in DVD is performed by a hollow-cathode plasmaunit capable of producing a high-density plasma in the system's gas andvapor stream, See FIGS. 7-9. The particular hollow cathode arc plasmatechnology used in DVD is able to ionize a large percentage of all gasand vapor species in the mixed stream flowing towards the coatingsurface. This ionization percentage in a low vacuum environment isunique to the DVD system. The plasma generates ions which can beaccelerated towards the coating surface by either a self-bias or by anapplied electrical potential. Increasing the velocity (and thus thekinetic energy) of ion by using an applied potential allows the energyof depositing atoms to be varied, affecting the atomic structure ofcoatings. The DVD process has the ability to combine focused evaporationwith plasma activation for rapid, efficient deposition of variouscrystal structures. The plasma device emits low energy electrons whichionize the vapor atoms and carrier gas. By properly biasing thesubstrate the impact energy the both species can be controlled.

Turning to FIG. 7, the major components of the present invention DVDsystem including a hollow cathode arc plasma activation and substratebias supply as schematically shown. The present invention DVD system iscomprises a vacuum chamber 304, a first rod feed evaporator 325(evaporant A & B) and second rod evaporator 326 (evaporant C) that areplaced and heated up to evaporation temperature of evaporant by theelectron-beam of an electron gun 303 and provides the vapor for coatingof substrates 320. Vaporized evaporant is entrained in the supersonicgas and vapor stream 315 formed by the nozzle 330. The substrate(s) 320are fixed at a substrate holder 343 which enables shift of the substratein any independent direction and to be swiveled. For example, thetranslation motion in the horizontal plan allows the exposed surfaceareas of the substrate to the vapor stream for defined dwelling timesand control of the local coating thickness. The vertical motion can beused to keep constant the distance between plasma and surface for curvedsubstrates. Swivel motion, in coordination with the translation motions,can be used to enable the coating of complete three-dimensional parts orcan be used also to change the incidence angle of the vapor particles inthe course of layer coating in a defined way for getting distinct layerproperties. The hollow cathode (arc source) 358 is placed laterallybelow substrate holder 343 with a short distance between the cathodeorifice 359 and the gas and vapor stream 315. The anode 360 is arrangedopposite the cathode orifice 359 (i.e., on an approximate distant sideof the stream 315) so that the fast electrons and the plasma discharge361 crosses the gas and vapor stream 315. The fixtures for the cathode346 and for the anode 347 provides the ability to adjust the distance ofthe cathode 358 and the anode 360, thereby influencing the diameter andthe shape of gas and vapor stream 315.

The plasma discharge 361 is in close proximity (arranged with shortdistance) to the surface of the substrate 320 enabling close contactbetween dense plasma and the substrate surface to be coated. In thevicinity of the evaporation electron-beam from the electron gun 303,.theanode power line 349 from the power generator 350 to the anode 360 isarranged closely and in parallel with both the plasma discharge 359 andthe cathode power line 351, which runs from the cathode to the powergenerator 350. Between the substrate 320 and the anode 360, a biasgenerator 352 is applied that allows for generation of a positive, anegative or a periodically alternating voltage between the substrate 320and the plasma 361.

FIG. 8 provides an enlarged partial view of the embodiment shown in FIG.7.

Turning to FIG. 9, FIG. 9 schematically illustrates an alternativeembodiment wherein the instant system and method has the main gas andvapor stream 315 which is deflected from the vertical direction 371 byinteraction with the working gas flow 372 of the hollow cathode 358escaping from the cathode orifice 359 resulting in a bending of thevapor stream 375 away from the cathode side. The directed gas injection373 is in an opposed position to the cathode through a gas channel 370integrated in the anode block 10 and enables the compensation ofdeflection. Therefore, the resulting gas and vapor stream 374 flows inthe vertical direction again. Overcompensation will result in a bendingof the main gas and vapor stream 376 towards the cathode side. The samechannel 370 can be used for clear gas influx to keep free the anode orparts of the anode surface from insulating contamination. This clear gasinflux feature can been done independently or in combination with thebending effect injection of the anode.

Other means for creating a plasma made up of the ionized evaporantand/or carrier gas atoms can be utilized including the use of microwaveor other radio frequency discharges. Once created, plasma enhanceddeposition is possible under the action of a self bias or one appliedexternally to the substrate. The applied bias can be static (DC) oroscillated (RF) or pulsed. Referring to FIGS. 10(A)-(B), in analternative embodiment an end-hall ion source is modified to function asthe evaporation and plasma creating system 401. FIGS. 10(A)-(B) shows amodified gridless ion source of the type described by Kaufman andRobinson (See Operation of Broad Beam Sources, by Harold R Kaufman andRaymond S. Robinson, Commonwealth Scientific Corp., Alexandria, Va., pp55-62, 1984, hereby incorporated by reference herein in its entirety).In the present invention approach a low voltage exterior electron beam435 or source is used to create a plasma in the throat of theevaporation source(s) 425, 426. The anode 436 is axisymmetric with acentral hole in which is fitted a water cooled crucible, which in turncontains one or a multiplicity of evaporation sources 425, 426.

Still referring to FIGS. 10(A)-(B), a brief description of sourceoperation is presented whereby typical operating sequences andprocedures are described. The various processes that occur in a modifiedend-Hall ion source 401. The neutral atoms or molecules 481 of theworking gas are introduced to the ion source through a port 431, such asHe gas jet. Electrons 482 created from the low voltage electron sourceapproximately follow magnetic field lines 483 back to the dischargeregion enclosed by the anode 436 and strike atoms or molecules 484therein. Some of these collisions produce ions 485. The mixture ofelectrons and ions in the discharge region forms a conductive gas, orplasma. Because the density of the neutral atoms or molecules falls offrapidly downstream of the anode 436 (toward the substrate/target 420)most of the ionizing collisions with neutrals occur in the regionsurrounded by the anode 436.

In conclusion, the present invention describes a series of steps, and anapparatus for use therewith for applying a bond coating to a substrateof a thermal barrier coating system using an electron beam directedvapor deposition technique, and more particularly providing a dispersionstrengthened bond coat that has an improved life expectancy bymitigating ill effects attributed to yield and creep.

Some advantages of the present invention process and apparatus, but notlimited thereto is that it provides for the materials utilizationefficiency of the process to be improved, deposition rate increased,coating uniformity improved, stable ceramic dispersoids in bond coatsfor greater yield and creep strength, multiple blade coating during eachcoating cycle, and carrier gas flow costs optimized.

In addition, the present invention provides for alloy strengthening inhigh temperature metallic alloys that can be melt or solid stateprocessed to materials that one applied by vapor deposition. The creepstrengthened coating contains nanoscopic particles of oxides, nitrides,borides, carbides, and other materials which are formed by reactivecodeposition. The present invention method, system, and resultantstructure may be utilized for, but not limited thereto, high temperaturecoatings, e.g. for protecting rocket gas turbine, or diesel enginecomponents.

Finally, an advantage of the present invention method, system, andresultant structure is that it, but not limited thereto, greatlyincreased coating lifetime (about 2-10 times greater) resulting fromelimination of coating spallation by the “rumpling” mechanism.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The foregoingembodiments are therefore to be considered in all respects illustrativerather than limiting of the invention described herein. Scope of theinvention is thus indicated by the appended claims rather than by theforegoing description, and all changes which come within the meaning andrange of equivalency of the claims are therefore intended to be embracedherein.

1. A method for forming a thermal barrier coating system, the methodcomprising the steps of: presenting at least one substrate; forming abond coat on at least a portion of at least one said substrate by adirected vapor deposition (DVD) technique; reactively formingdispersoids in said bond coat; and depositing a thermal-insulating layeron said bond coat.
 2. The method of claim 1, wherein said dispersoidscomprise an oxygen compound.
 3. The method of claim 1, wherein saiddispersoids comprise at least one of Oxide, Carbide, Boride, Nitride,Oxycarbide, Carbonitride, Carbonoxide, Mn, Cr, Fe, Ni, Sc, Hf, Ti, V,Zr, Al, Nb, Ta, Si, or W, or combination thereof.
 4. The method of claim1, wherein said DVD techinique comprises: said presenting of at leastone of said substrate includes presenting said substrate to a chamber,wherein said chamber has an operating pressure ranging from about 0.1 toabout 32,350 Pa,; presenting at least one evaporant source to saidchamber; presenting at least one carrier gas stream to said chamber;impinging said at least one said evaporant source with at least oneenergetic beam in said chamber to generate an evaporated vapor flux in amain direction respective for any of said evaporant sources impinged bysaid electron beam; and deflecting at least one of said generatedevaporated vapor flux by at least one of said carrier gas stream,wherein said carrier gas stream is essentially parallel to the maindirection and substantially surrounds said evaporated flux, wherein saidevaporated vapor flux at least partially coats at least one saidsubstrate to form said bond coat.
 5. The method of claim 4, wherein saidenergetic beam comprises at least one of electron beam source, lasersource, heat source, ion bombardment source, highly focused incoherentlight source, microwave, radio frequency, EMN, or any energetic beamthat break chemical bonds, or combination thereof.
 6. The method ofclaim 4, further comprising: said chamber further includes a substratebias system capable of applying a DC or alternating potential to atleast one of said substrates; impinging said at least one of saidgenerated vapor flux and at least one of said carrier gas stream with aworking gas generated by at least one hollow cathode arc plasmaactivation source to ionize said at least one of said generated vaporflux and at least one of said carrier gas stream; and attracting saidionized generated vapor flux and said carrier gas stream to a substratesurface by allowing a self-bias of said ionized gas and vapor stream orsaid potential to pull the ionized stream to said substrate.
 7. Themethod of claim 6, said generated electrons from said hollow cathodesource is regulated for direction through variations in the quantity ofworking gas passing through said hollow cathode source.
 8. The processof claim 6, wherein the distance between said cathode source and saidgenerated evaporated vapor flux is regulated for ionization of theentire generated evaporated vapor flux.
 9. The method of claim 4,further comprising at least one nozzle, wherein said at least onecarrier gas stream is generated from said at least one nozzle and saidat least one evaporant source is disposed in said at least one nozzle,wherein said at least one said nozzle comprises: at least one nozzle gapwherein said at least one said carrier gas flows there from; and atleast one evaporant retainer for retaining at least one said evaporantsource, said evaporant retainer being at least substantially surroundedby at least one said nozzle gap.
 10. The method claim 9, wherein saidevaporant retainer is a crucible.
 11. The method of claim 4, furthercomprising: said chamber further includes a substrate bias systemcapable of applying a DC or alternating potential to at least one ofsaid substrates; impinging said at least one of said generated vaporflux and at least one of said carrier gas stream with a low energy beamto ionize said at least one of said generated vapor flux and at leastone of said carrier gas stream; and attracting said ionized generatedvapor flux and said carrier gas stream to a substrate surface byallowing a self-bias of said ionized gas and vapor stream or saidpotential to pull the ionized stream to said substrate.
 12. The methodof claim 4, wherein at least one of said at least one evaporant sourceis a material selected from the group consisting: NiY, NiAl, PtAl, PtY,Ni, Y, Al, Pt, NiAlPt, NiYPt, NiPt, Co, Mo, Fe, Zr, Hf, Yb, and otherreactive elements.
 13. The method of claim 4, wherein at least one ofsaid at least one evaporant sources is made from alloys formed of one ormore of a material selected from the group consisting: NiY, NiAl, PtAl,Pty, Ni, Y, Al, Pt, NiAlPt, NiYPt, NiPt, Co, Mo, Fe, Zr, Hf, Yb, andother reactive elements.
 14. A method for forming a thermal barriercoating system, the method comprising the steps of: presenting at leastone substrate; forming a bond coat on at least a portion of at least onesaid substrate by a directed vapor deposition (DVD) technique; providingnanoclusters under a pressure greater than said chamber pressure; andinjection said nanoclusters at a high velocity into the said chamber,thereby resulting in dispersoids impinged in said bond coat.
 15. Themethod of claim 14, further comprising: depositing a thermal-insulatinglayer on said bond coat.
 16. A directed vapor deposition (DVD) apparatusfor forming a thermal barrier coating system, the apparatus comprising:a chamber, wherein said chamber has an operating pressure ranging fromabout 0.1 to about 32,350 Pa, wherein at least one substrate ispresented in said chamber; at least one evaporant source disposed insaid chamber; at least one carrier gas stream provided in said chamber;and an energetic beam system providing at least one energetic beam, saidenergetic beam: impinging at least one said evaporant source with atleast one said energetic beam in said chamber to generate an evaporatedvapor flux; and deflecting at least one of said generated evaporatedvapor flux by at least one of said carrier gas stream, wherein saidevaporated vapor flux at least partially coats at least one of saidsubstrates to form a bond coat and reactively forms dispersoids in saidbond coat.
 17. The method of claim 16, wherein said dispersoids comprisean oxygen compound.
 18. The method of claim 16, wherein said dispersoidscomprise at least one of Oxide, Carbide, Boride, Nitride, Oxycarbide,Carbonitride, Carbonoxide, Mn, Cr, Fe, Ni, Sc, Hf, Ti, V, Zr, Al, Nb,Ta, Si, or W, or combination thereof.
 19. The apparatus of claim 16,further comprising: said energetic beam system providing at least oneenergetic beam, said energetic beam: impinging at least one of saidevaporant source with at least one said energetic beam in said chamberto generate an evaporated vapor flux; and deflecting at least one ofsaid generated evaporated vapor flux by at least one of said carrier gasstream, wherein said evaporated vapor flux at least partially coats atleast one of said substrates to form a thermal-insulating layer on saidbond coat with said dispersoids therein.
 20. The method of claim 16,wherein said energetic beam comprises at least one of electron beamsource, electron gun source, laser source, heat source, ion bombardmentsource, highly focused incoherent light source, microwave, radiofrequency, EMF, or any energetic beam system that breaks chemical bonds,or combination thereof.
 21. The apparatus of claim 16, wherein: saidgenerated evaporated vapor flux is in a main direction respective forany of said evaporant sources impinged by said energetic beam; andwherein said carrier gas stream is essentially parallel to the maindirection and substantially surrounds said generated evaporated flux.22. The apparatus of claim 16, further comprising: a substrate biassystem capable of applying a DC or alternating potential to at least oneof said substrates; at least one hollow cathode arc source generating alow voltage beam, said at least one hollow cathode arc source: impingingsaid at least one of said generated vapor flux and at least one of saidcarrier gas stream with a working gas generated by at least one saidhollow cathode arc plasma activation source to ionize said at least oneof said generated vapor flux and at least one of said carrier gasstream; and attracting said ionized generated vapor flux and saidcarrier gas stream to a substrate surface by allowing a self-bias ofsaid ionized gas and vapor stream or said potential to pull the ionizedstream to said substrate.
 23. The apparatus of claim 22, wherein saidhollow cathode arc source comprises at least one cathode orifice whereina predetermined selection of said cathode orifices are arranged in closeproximity to the gas and vapor stream; and an anode is arranged oppositeof said cathode source wherein the gas and vapor stream is there betweensaid cathode source and said anode.
 24. The apparatus of claim 16,further comprising at least one nozzle, wherein said at least onecarrier gas stream is generated from said at least one nozzle and saidat least one evaporant source is disposed in said at least one nozzle,wherein said at least one said nozzle comprises: at least one nozzle gapwherein said at least one said carrier gas flows there from; and atleast one evaporant retainer for retaining at least one said evaporantsource, said evaporant retainer being at least substantially surroundedby at least one said nozzle gap.
 25. The apparatus of claim 24, whereinsaid evaporant retainer is a crucible.
 26. The apparatus of claim 16,further comprising: a substrate bias system capable of applying a DC oralternating potential to at least one of said substrates; at least onelow energy beam source for generating a low voltage beam, said at leastone low energy beam source: impinging said at least one of saidgenerated vapor flux and at least one of said carrier gas stream with alow energy beam to ionize said at least one of said generated vapor fluxand at least one of said carrier gas stream; and attracting said ionizedgenerated vapor flux and said carrier gas stream to a substrate surfaceby allowing a self-bias of said ionized gas and vapor stream or saidpotential to pull the ionized stream to said substrate.
 27. A componenthaving a thermal barrier coating system on a substrate thereof, thethermal barrier coating system comprising: a bond coat deposited on atleast a portion of said substrate by a directed vapor deposition (DVD)technique, wherein said bond coat comprises dispersoids in said bondcoat.
 28. The component of claim 27, further comprising: athermal-insulating layer overlying at least a portion of said bond coat.29. The component of claim 27, wherein said component is produced by themethod of claim
 2. 30. The component of claim 27, wherein said componentis at least one of: gas turbine engine component, diesel enginecomponent, turbine blade, and airfoil.